What worked for me is finding one used!! So much cheaper! I got a 60g with stand and hood and lights, gravel. I had to buy a filter and another heater. All together about 150 bucks!! Good luck
My 60g is about 48 x 18 x 12 FYI
Here's another tip to calculate a rough volume quickly:
(L X W X H ) / 231
For example, a standard 55 is (48X13X20)/231=54.03. Sorry to break the news Holly, but 48X18X12 is a 45 gallon. Didn't want to be cruel, but you should know for dosing and other reasons. Sorry.